package leecode;

public class LeetCode34 {
    public int numTrees(int n) {
        int[]G=new int[n+1];
        G[0]=1;
        G[1]=1;
        for(int i=2;i<=n;++i){
            for(int j=1;j<=i;++j){
                G[i]+=G[j-1]*G[i-j];
            }
        }
        return G[n];
    }
}
